Machine press with positive cam driven sliding bed and cam activated auxiliary systems

ABSTRACT

A machine press is disclosed having a base and vertical supports upstanding therefrom, a motor-driven crankshaft rotatably mounted in the vertical supports, and a ram mounted for vertical sliding movement driven by a connecting rod interconnecting the crankshaft and the ram. A bed is mounted for horizontal sliding movement under the ram, and is driven by a cam engaging two cam followers upstanding from the bed. The cam is connected to a shaft which is driven from the crankshaft through two-to-one reduction bevel gears. The cam is symmetrical, and provides two zero velocity positions of the bed coordinated with the lowermost position of the ram. Die sets comprising a plurality of steppedheight dies arrayed parallel to the motion of the sliding bed are mounted in the machine press; the lower half of the die set being mounted on the sliding bed, and the upper half being mounted on the ram. The dies come together for a stamping operation when the bed is at a first zero velocity position, and the dies are indexed one die for transfer operations when the bed is at its second zero velocity position. Additional cams are mounted on the second shaft, and these cams operate sensors controlling auxiliary devices, such as parts ejectors and missing parts detectors.

United States Patent Blase MACHINE PRESS WITH POSITIVE CAM DRIVENSLIDING BED AND CAM ACTIVATED AUXILIARY SYSTEMS Primary ExaminerC. W.Lanham Assistant ExaminerGene P. Crosby Attorney, Agent, orFirm-Mattern, Ware & Davis [57] ABSTRACT A machine press is disclosedhaving a base and vertical supports upstanding therefrom, a motor-drivencrankshaft rotatably mounted in the vertical supports, and a ram mountedfor vertical sliding movement driven by a connecting rod interconnectingthe crankshaft and the ram. A bed is mounted for horizontal slidingmovement under the ram, and is driven by a cam engaging two camfollowers upstanding from the bed. The cam is connected to a shaft whichis driven from the crankshaft through two-to-one reduction bevel gears.The cam is symmetrical, and provides two zero velocity positions of thebed coordinated with the lowermost position of the ram. Die setscomprising a plurality of stepped-height dies arrayed parallel to themotion of the sliding bed are mounted in the machine press; the lowerhalf of the die set being mounted on the sliding bed, and the upper halfbeing mounted on the ram. The dies come together for a stampingoperation when the bed is at a first zero velocity position, and thedies are indexed one die for transfer operations when the bed is at itssecond zero velocity position. Additional cams are mounted on the secondshaft, and these cams operate sensors controlling auxiliary devices,such as parts ejectors and missing parts detectors.

14 Claims, 9 Drawing Figures [76] Inventor: Robert Blase, 1009 RoundHill Rd.,

F i LCQa -WBQ [22] Filed: Nov. 20, 1973 [21] Appl. No.: 417,579

Related U.S. Application Data [63] Continuation-impart of Ser. No.301,165, Oct. 26,

1972, abandoned.

[52] i U.S. Cl 72/405, 72/4, 72/421 [51] Int. Cl B2lj 13/08 [58] Fieldof Search 72/405, 421, 448, 452, 72/4, 26; 10/125, 12 T, 76 T; 198/218[56] References Cited UNlTED STATES PATENTS 1,426,039 8/1922 Candee198/218 2,663,275 12/1953 Collins 72/4 2,886,886 5/1959 Hartung 72/4213,031,698 5/1962 Friedman l0/l2.5

3,247,533 4/1966 Phipard l0/l2.5 3,319,087 5/1967 Wintriss.... 72/263,369,387 2/1968 Bradlee..... 72/426 3,527,073 9/1970 Wintriss.... 72/43,541,834 11/1970 Wallis 72/405 3,555,861 l/l971 Staecker 72/4 3,555,8651/1971 Sebastian 72/448 PATENTEDJANZBIQTE 3,862,564

SHEET 10F 2 PATENTEU sum 2 or 2 FIG. 6

FIG. 5

MACHINE PRESS WITH POSITIVE CAM DRIVEN SLIDING BED AND CAM ACTIVATEDAUXILIARY SYSTEMS CROSS-REFERENCE This application is acontinuation-in-part application of Robert Blases patent applicationrelating to Machine Press with Positive Cam Driven Sliding Bed and CamActivated Auxiliary Systems filed Oct. 26, 1972 and bearing Ser. No.301,165, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to machine presses, and particularly to machine presses withsliding beds for performing transfer operations. The invention furtherrelates to machine presses having sliding beds positively driven by camswherein the sliding beds are accurately positioned and wherein ejectors,missing parts detectors, and the like are also positively actuated bycams.

2. Prior Art Machine presses having a bed slidable under a verticallydriven press member are known in the prior art. However, the prior artpresses have employed various compressed air or pneumatic means fordriving the bed. Typically, mechanical stops determine the position ofthe bed, and complicated series of relays controlling the supply ofcompressed air were used to drive the bed. Similarly, accessories suchas ejectors were also electric-air driven, being operated by compressedair passed through a series of air relays which were in turn controlledby mechanical sensors for sensing the position of the bed and ram.

These devices were unsatisfactory in many respects. First, thepositioning of the sliding bed was not precise. Also, most of thepresses having beds driven by compressed air exhibited a high amount ofvibration. The vibration contributed to inaccuracy and also shortenedthe life of the dies and the slide mechanism on which the bed wasmounted.

In addition, the relays required to drive a sliding bed were extremelycomplicated, and required frequent repair. The repairs themselves wereexpensive, and also resulted in considerable down time and consequentloss of production.

SUMMARY OF THE INVENTION OBJECTS It is an object of this invention toprovide improved machine presses having sliding beds.

It is a second object of this invention to provide machine presseshaving reliably and efficiently driven auxiliary devices.

It is an additional object of the invention to provide machine pressesof the type having sliding beds wherein the sliding beds are accuratelypositioned for press operation.

It is an additional object of the invention to provide machine pressessuitable for producing precision parts.

It is a further object of the invention to provide machine presses whichare highly reliable and durable.

GENERAL DESCRIPTION tached to an overhead motorized crankshaft. A bed ismounted for sliding horizontal motion below the ram, and the secondportion of the die set is carried on the sliding bed.

The sliding bed is connected to and driven from the crankshaft by apositive mechanical link comprising a shaft driven by the crankshaftthrough 2:1 gearing, a cam connected to the shaft and positionedadjacent to the sliding bed, and cam followers attached to the slidingbed and engaging the cam. The cam used to drive the bed provides amodified sinusoidal variation of velocity and acceleration wherein thebed is stationary at the time of contact between the two die sets andwhen the die sets are in close aligned proximity for transferoperations.

Additional cams are mounted on the crankshaft and shaft, and are used toactuate auxiliary devices including parts ejectors, bed positionmonitors, missing parts detectors, operator safety restraints oroperator position sensors, or the like.

Other and more specific objects will be apparent from the features,elements, combinations and operating procedures disclosed in thefollowing description of the preferred embodiment and shown in thedrawings.

THE DRAWINGS FIG. 1 is a front view of a machine press according to theinvention with its die set aligned for a transfer operation;

FIG. 2 is a sectional view of the cam, sliding bed, and relativepositions of the dies of the machine press taken along the lines 2--2 ofFIG. 1;

FIG. 3 is a front view partially cut away of the machine press of FIG. 1with its die sets aligned for form- FIG. 4 is a sectional view of thecam, sliding bed, and relative positions of the dies of the machinepress taken along the lines 44 of FIG. 3;

FIG. 5 is a vertical sectional view of the sliding bed and its base,taken along the lines 55 of FIG. 2;

FIG. 6 is an enlarged sectional view of a parts ejector mechanismencircled in FIG. 3;

FIG. 7 is a schematic electrical diagram of a bed position monitor ofthe machine press of FIG. 1;

FIG. 8 is a framentary schematic diagram of a missing parts detector ofthe present invention; and

FIG. 9 is a similar fragmentary schematic diagram of a modified versionof the missing parts detector of FIG. 8.

The same reference numbers refer to the same elements throughout thedrawings.

PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a machinepress 10 according to the invention. The press comprises a base 11having a sliding bed assembly 12 mounted thereon. The sliding bedassembly comprises a first portion 13 secured to the base 11 and havinga V-shaped spline 14 comprising the male portion of a dovetailupstanding therefrom. A sliding bed 15 is mounted for linear slidingmotion on plate 13, the sliding bed 15 having a groove 16 comprising thefemale portion of the dovetail. As best seen in FIG. 5, the V- shapedspline 14 and the groove 16 cooperate to hold the sliding bed 15 ontothe base and to permit linear motion thereof. Bearings may be providedat the interface of the groove 16 and the spline 14.

The machine press further comprises two supports and 21 upstanding fromthe base 11, and a top plate 22 connecting the two vertical supports.Mounted on the top plate 22 is an electric motor or variable speed drivemeans 23 having an output shaft 24 and associated pulley 25. A drivebelt 26 is engaged by the pulley and by a combination brake, clutch, andfly wheel 27 which is mounted onto a shaft 30 supported in bearings inthe two vertical supports 20 and 21. The shaft 30 has an offset portion31, wherein the shaft 30 operates as a crankshaft.

The machine press 10 further comprises a ram 32 'slidingly mounted forvertical movement on vertical guides 33 and 34. A connecting rod 35 isconnected to the ram 32 at one end and is connected to the offsetportion 31 of the shaft 30 at its other end, wherein the ram 32 makesone complete up-and-down stroke for each rotation of the shaft 30.

A first bevel gear 36 is mounted on the free end of shaft 30 adjacent tovertical support 20. The bevel gear 36 cooperates with a second bevelgear 37 to rotate a vertical shaft 40 connected to bevel gear 37. Thevertical shaft 40 is supported by two bearings 41 and 42 which are inturn supported on the vertical support 20. A third bearing (not shown)suports the lower end of shaft 40. The shaft 40 is connected to androtates a cam 43. The cam 43 is positioned adjacent to the sliding bed15, and upstanding from the sliding bed 15 are two cam followers 44 and45, wherein the sliding bed 15 is driven and accurately positioned bythe cam 43, and wherein a positive mechanical link between the slidingbed 15 and the vertical sliding ram 32 is provided.

The bevel gears 36 and 37 have a 2:1 ratio, i.e. the shaft 40 is drivenat V2 the speed of the speed of the shaft 30. The shape of cam 43, bestseen in FIGS. 2 and 4, causes the sliding bed 15 to be driven throughone in-and-out cycle for each rotation of shaft 40. The surface of cam43 has a zero speed portion 46 wherein the surface of the cam is at aconstant radius from the shaft 40. Referring now to FIG. 2, the zerospeed protion 46 causes the sliding bed to be at rest with respect tothe base at the outermost position of travel of the bed. The zero speedposition of bed 15 is coordinated with the motion of ram 32 so that thelowermost portion of travel of ram 32 occurs when the bed 15 ismotionless.

Referring now to FIGS. 3 and 4, a second zero speed position of bed 15occurs at the innermost position achieved by bed 15. Again, thelowermost portion of vertical travel of the second downward cycle of ram32 occurs while the bed is motionless.

A die set 50 is mounted in the machine press 10 for forming or stampingparts. The die set 50 comprises a lower plate 51 secured to the slidingbed 15. Upstanding from the lower plate 51 are four individual dies52-55 having progressively less vertical height. A second set ofcooperating dies 62-65 are mounted on a plate 56 secured to the ram 32.The dies 62-65 have progressively increasing vertical height, incrementof increase being the same as the increment of decrease in height ofdies 52-55. Die sets with any number of dies can be used, and four diesare shown for convenience. The lower dies 52-55 and the upper dies 62-65are precisely aligned for performing stamping operations when the bed 15is in its innermost position and the ram 32 is at its lowermostposition, as shown in FIGS. 3 and 4. To better insure the precisealignment of the dies during both stamping and transfer operations,upstanding auxiliary guides such as guide 66, are provided on the lowerdie set plate 51, and mating receptacles such as receptacle 67, areprovided on the upper plate 56.

Subsequent to stamping or forming operations, the parts are carried onthe upper dies 62-65 for one upand-down cycle of the ram 32, duringwhich time the bed 15 is driven to its outermost position shown in FIGS.1 and 2. The die 62 is then aligned with die 53, and the like, and upperdie 65 is positioned over a collection container 70. The upper and lowerdies do not touch because of the incremented vertical heights thereof.When the dies are aligned and the ram 32 is at its lowermost position,parts ejectors forming a portion of the upper die set operate to depositthe parts carried on the die set onto the lower dies, e.g. the partformed between upper die 62 and lower die 52 is deposited onto lower die53, whereby a further forming or stamping operation will be performed onthe part between upper die 63 and lower die 53 on the next verticalcycle of the ram 32.

Referring now to FIG. 6, a typical parts ejector mechanism is shown at71. It comprises one or more vertical rods 72 passing through the upperdie 62. The vertical rods 72 butt against one end of a movableair-driven piston 73, which is provided with air through conduit 74connected to a source of positive pressure through valve means.Synchronization of the valve opening and the motion of the sliding bedand ram are preferably coordinated by attaching an auxiliary cam 75 toshaft 40 and attaching a mechanical finger or other mechanical sensor 76in the path of cam 75. The mechanical sensor 76 preferably directlyoperates an air valve wherein air is admitted through conduit 74 to movepiston 73 and drive down the shafts 72 to eject the part. The sensor 76can also operate an electric relay to accomplish the same purpose.Because of the reduced speed of shaft 40, the ejector is operated onlyon alternate vertical strokes of ram 32, as desired.

Other auxiliary cams can also be connected to shaft 40 for operatingsensors adjacent thereto. For instance. there are shown auxiliary cams77 and 81 (FIG. I) mounted on shaft 40 for operating sensors 80 and 82each revolution of shaft 40. Cam 77 is positioned to trigger the sensoras the ram approaches its lowermost position, and is therefore useful incooperation with safety devices for causing a brake to operate and stopthe ram if the operators hands are not clear. The third auxiliary cam 81attached to shaft 40 has a cooperating sensor 82 for activating amissing parts detector on each transfer stroke. The missing partsdetector may be a photoelectric sensor positioned between upper die 65and collection basket 70, and may provide an alarm signal for stoppingthe press if no part is produced.

Two highly useful forms of missing parts detectors are shown in FIGS. 8and 9. In FIG. 8, the completed parts container 70 is replaced by adelivery chute 70A leading to a remote collection 708. A lateraldelivery conduit 76 has its entrance juxtaposed to final upper die part65 and its exit facing delivery chute 70A. An air jet 77 propels eachcompleted part 78 ejected from die part 65 into and through conduit 76and thence into chute 70A. An inductive sensor ring 79 encircles conduit76 and is connected to a ready-or-stop control unit or stop alarm likethat shown in FIG. 7.

In the alternative version of the missing parts detector shown in FIG.9, the delivery chute 70A and lateral conduit 76 are combined in avertically-oriented conduit 76A interposed between the overlying finaldie part 65 and the underlying remote collection container 708. Sensorring 79 surrounds conduit 76A, performing the identical functiondescribed above. Air jet 77 is here replaced by the force of gravity, orby a downwardly-acting air jet 77A incorporated in upper die part 65.

In both forms of these missing parts detectors, capacitive sensors orphotocell sensors may be employed if desired, in place of inductivesensor 79. Output signals from sensor 79, and cycle-in-progress signalsfrom sensor 80 or 82 for example, are both supplied to the stop alarmunit. Omission of either signal triggers the alarm which is connected tostop the press at once for inspection.

If for any reason a part is not ejected, it may cause successivestacking of a dozen or more parts between the die sets, creating dangerof tooling damage or destruction. Such damage is avoided by the missingparts detectors of this invention, since the absence of a signal fromsensor ring 79 during any operating cycle stops the press instantly, topermit removal of stacked or jammed parts. Human operators assigned tomonitor these automatic stamping presses may become hypnotized bywatching repeated operating cycles, hour after hour, and may fail tonotice stacked part jams until damage has already occurred. The missingparts detector systems of this invention sense the first missing part,making these stamping presses fully automatic for longsustainedcontinuous operation.

Auxiliary cams can also be installed on crank shaft 30. Such cams rotateonce per revolution of shaft 30, and twice per revolution of shaft 40,and therefore rotate once per vertical stroke of ram 32 and once foreach complete in-out cycle of sliding bed 15.

Cam 90 is shown mounted on crank shaft 30 for operating sensor 91. Cam90 and sensor 91 are a portion of a bed position monitoring system whichfurther includes right and left micro-switches (shown only in FIG. 7),the right micro-switch being closed when the bed is in its far rightposition and the left micro-switch being closed by the bed in its farleft position. The object of the monitoring system is to provide asignal for operating the brake if the sliding bed does not operate themicro-switches at the proper time, indicating some malfunction.

Referring now to FIG. 7, the right micro-switch 92 and the leftmicro-switch 93 are wired in parallel with the sensor 91. Cam 90 ispreferably a holding cam, i.e. during a substantial portion of itsrotation it holds sensor 91 closed and is timed to open sensor 91 justafter either sensor 92 or 93 is closed by the arrival of the sliding bedand is further timed to close sensor 91 just before the movement of thesliding bed opens microswitch 92 or 93. Therefore, so long as thesliding bed reaches its proper position at the proper time, and so longas the shaft 30 is intact and rotating cam 90, a signal is provided at94. However, if the sliding bed should fail to arrive at the proper timeto close one of the micro-switches 92 or 93, or if the shaft 30 shouldbreak or become displaced, no signal is provided at 94, therebyactivating the brake mechanism and stopping further operation of thepress.

Other shapes of cam 43 may be substituted to provide various types ofsliding bed motion relative to the vertical ram 32. For instance, thebed may be caused to stop in three positions with an appropriate cam ifthe progression of the work pieces through the dies so requires. Also,additional auxiliary cams can be mounted on shaft 40 to run a variety ofother auxiliary devices, such as counters, lubrications sprays, paintsprays, and the like.

The machine press described herein is sturdy and runs relatively free ofvibration, wherein long life, low maintenance cost, and little down timecan be expected. The machine press is adaptable to a variety ofoperations by substituting die sets, bed driving cams, auxiliary camsand sensing devices.

Since the foregoing description and drawings are merely illustrative,the scope of the invention has been broadly stated herein and it shouldbe liberally interpreted to secure the benefit of all equivalents towhich the invention is fairly entitled.

I claim:

1. A machine press comprising:

A. a base and supports upstanding therefrom;

B. a first motor-driven upper shaft rotatably mounted in the supportsupstanding from the base;

C. a ram mounted for sliding movement perpendicular to the base;

D. connecting means for driving the ram from the first upper shaft;

E. a bed mounted for sliding movement on the base, said sliding movementbeing perpendicular to the movement of the ram;

F. a second shaft driven by the first shaft;

G. A first cam mounted on said second shaft adjacent to the bed;

H. cam followers upstanding from the bed and engaged by the first cam,wherein rotation of the second shaft and the first cam mounted thereoncauses sliding movement of the bed.

2. A machine press as defined in claim 1 and further comprising:

1. at least one additional cam mounted on said second shaft; and

J. sensor means activated by said additional cam for controlling theoperation of auxiliary devices.

3. A machine press as defined in claim 1 wherein the second shaft isdriven by the first shaft through twoto-one reduction gears.

4. A machine press as defined in claim 3 wherein said first anclv secondshafts are perpendicular, and wherein the reduction gears are bevelgears.

5. A machine press as defined in claim 3 wherein the first cam issymmetrical and provides a first zero velocity position of the bed whenthe ram is in closest proximity to the bed, and further provides asecond zero velocity position of the bed when the ram is next in closestproximity to the bed.

6. A machine press as defined in claim 5 wherein the first half of amultiple-die die set is mounted on the vertical ram and the second halfof the multiple-die die set is mounted on the sliding bed and whereinthe dies of the first and second halves of the die set are aligned inthe first zero velocity position of the bed for forming operations, andwherein some of the dies of the first and second die sets are aligned inthe second zero velocity position of the bed for transfer operations.

7. A machine press as defined in claim 2 wherein one of auxiliarydevices is a parts ejector.

8. A machine press as defined in claim 2 wherein one of the auxiliarydevices is a missing parts detector.

9. A machine press as defined in claim 1 and further comprising:

l. at least one additional cam mounted on said first shaft; and

J. sensor means activated by said additional cam for controlling theoperation of auxiliary devices.

10. A machine press as defined in claim 9 wherein one of the auxiliarydevices is a bed position sensor comprising:

a. a first micro-switch operated by the bed in a first position;

b. a second micro-switch operated by the bed in a second position;

0. means connecting the first micro-switch, the second micro-switch, andthe sensor means in parallel, wherein the additional cam mounted on thefirst shaft is designed to change the condition of the sensor meansduring a portion of the period when either the first or secondmicro-switch is operated by the sliding bed.

11. The machine press defined in claim 8 wherein the missing partsdetector comprises a completed part ejection conduit positioned toreceive each completed part ejected from between die parts respectivelymounted on the ram and the bed, and a proximity sensor juxtaposed to theconduit and connected to produce an output signal in response to thepassage of each completed part through the conduit, and a stop alarmunit connected to receive said output signals and to stop the pressoperation if an output signal is not generated during each pressoperating cycle.

12. The machine press defined in claim 11 wherein the conduit extendslaterally toward a remote collection point, and further including an airjet directed to propel each ejected part into said ejection conduit.

13. The machine press defined in claim 11 wherein said ejection conduithas an entrance portal positioned directly below the ejected parts,whereby they are delivered into said portal.

14. A machine press comprising:

A. a base and supports upstanding therefrom;

B. a first motor-driven upper shaft rotatably mounted in the supportsupstanding from the base;

C. a ram mounted for sliding movement perpendicular to the base;

D. connecting means for driving the ram from the first upper shaft;

E. a bed mounted for sliding movement on the base, said sliding movementbeing perpendicular to the movement of the ram; and

F. a missing parts detector comprising a conduit through which eachcompleted part is ejected, and a proximity sensor associated with theconduit and providing an output signal to a stop alarm unit connected tostop press operation if a completed part sensing output signal is nottransmitted during any operating cycle.

1. A machine press comprising: A. a base and supports upstandingtherefrom; B. a first motor-driven upper shaft rotatably mounted in thesupports upstanding from the base; C. a ram mounted for sliding movementperpendicular to the base; D. connecting means for driving the ram fromthe first upper shaft; E. a bed mounted for sliding movement on thebase, said sliding movement being perpendicular to the movement of theram; F. a second shaft driven by the first shaft; G. A first cam mountedon said second shaft adjacent to the bed; H. cam followers upstandingfrom the bed and engaged by the first cam, wherein rotation of thesecond shaft and the first cam mounted thereon causes sliding movementof the bed.
 2. A machine press as defined in claim 1 and furthercomprising: I. at least one additional cam mounted on said second shaft;and J. sensor means activated by said additional cam for controlling theoperation of auxiliary devices.
 3. A machine press as defined in claim 1wherein the second shaft is driven by the first shaft through two-to-onereduction gears.
 4. A machine press as defined in claim 3 wherein saidfirst and second shafts are perpendicular, and wherein the reductiongears are bevel gears.
 5. A machine press as defined in claim 3 whereinthe first cam is symmetrical and provides a first zero velocity positionof the bed when the ram is in closest proximity to the bed, and furtherprovides a second zero velocity position of the bed when the ram is nextin closest proximity to the bed.
 6. A machine press as defined in claim5 wherein the first half of a multiple-die die set is mounted on thevertical ram and the second half of the multiple-die die set is mountedon the sliding bed and wherein the dies of the first and second halvesof the die set are aligned in the first zero velocity position of thebed for forming operations, and wherein some of the dies of the firstand second die sets are aligned in the second zero velocity position ofthe bed for transfer operations.
 7. A machine press as defined in claim2 wherein one of auxiliary devices is a parts ejector.
 8. A machinepress as defined in claim 2 wherein one of the auxiliary devices is amissing parts detector.
 9. A machine press as defined in claim 1 andfurther comprising: I. at least one additional cam mounted on said firstshaft; and J. sensor means activated by said additional cam forcontrolling the operation of auxiliary devices.
 10. A machine press asdefined in claim 9 wherein one of the auxiliary devices is a bedposition sensor comprising: a. a first micro-switch operated by the bedin a first position; b. a second micro-switch operated by the bed in asecond position; c. means connecting the first micro-switch, the secondmicro-switch, and the sensor means in parallel, wherein the additionalcam mounted on the first shaft is designed to change the condition ofthe sensor means during a portion of the period when either the first orsecond micro-switch is operated by the sliding bed.
 11. The machinepress defined in claim 8 wherein the missing parts detector comprises acompleted part ejection conduit positioned to receive each completedpart ejected from between die parts respectively mounted on the ram andthe bed, and a proximity sensor juxtaposed to the conduit and connectedto produce an output signal in response to the passage of each completedpart through the conduit, and a stop alarm unit connected to receivesaid output signals and to stop the press operation if an output signalis not generated during each press operating cycle.
 12. The machinepress defined in claim 11 wherein the conduit extends laterally toward aremote collection point, and further including an air jet directed topropel each ejected part into said ejection conduit.
 13. The machinepress defined in claim 11 wherein said ejection conduit has an entranceportal positioned directly below the ejected parts, whereby they aredelivered into said portal.
 14. A machine press comprising: A. a baseand supports upstanding therefrom; B. a first motor-driven upper shaftrotatably mounted in the supports upstanding from the base; C. a rammounted foR sliding movement perpendicular to the base; D. connectingmeans for driving the ram from the first upper shaft; E. a bed mountedfor sliding movement on the base, said sliding movement beingperpendicular to the movement of the ram; and F. a missing partsdetector comprising a conduit through which each completed part isejected, and a proximity sensor associated with the conduit andproviding an output signal to a stop alarm unit connected to stop pressoperation if a completed part sensing output signal is not transmittedduring any operating cycle.